Halogen light bulbs use about 20 to 30 percent less electricity than incandescent light bulbs, so they're not nearly as efficient as compact fluorescent or LED light bulbs. They also don't last as long. While many CFL bulbs are rated to last an average of 10,000 hours, and incandescents generally last around 1,000 hours each, halogen bulbs are usually rated to last about 3,000 hours. Still, halogen bulbs have some distinct advantages. Unlike compact fluorescents, halogen bulbs turn on instantly and are fully dimmable, so they can be used with standard dimmer switches. Frequent on-off cycling doesn't shorten the lifetime of halogen light bulbs, so they're suitable for use in fixtures where a compact fluorescent light bulb would burn out prematurely. Lastly, particularly in the review at The New York Times, testers enjoyed the quality of light from halogen bulbs.
Halogen light bulbs are also safer for the environment because they contain no mercury. This means they can be disposed of in ordinary household trash and pose no special risks if broken. Experts recommend halogen lighting for displaying colors to advantage, often describing the light as crisp and clear. It's also good for task lighting. At Shahine.com, Microsoft product manager Omar Shahine refers to the Osram Sylvania website section comparing incandescent bulbs and halogen bulbs, which states that halogen bulbs have a higher color temperature than incandescent bulbs, making them appear whiter and brighter. Shahine finds the color temperature of halogen bulbs pleasing.
For medium-base fixtures, we found the most reviews for Philips Halogena Energy Saver light bulbs (*Est. $12 for two). A 70-watt Halogena Energy Saver light bulb can replace a 100-watt incandescent (producing 1,600 lumens). A 40-watt bulb is also available (*Est. $17 for two), producing 800 lumens to replace a 60-watt incandescent. This provides enough savings to meet the new U.S. standards that go into effect in 2012. (By 2020, however, light bulbs must be 70 percent more efficient.) These light bulbs are rated at about 3,000 hours.
The pear shape, often called an A-shape, is similar to that of most incandescent light bulbs, so lampshades can clip onto the Halogena light bulb. Rated at 3,000K, the halogen light is only slightly cooler than the 2,700K of typical incandescent light bulbs -- and slightly cooler than warm or soft white compact fluorescents.
Philips Halogena Energy Saver bulbs are recommended in two comparison reviews. Both reviews directly compare halogen light bulbs with several brands and colors of compact fluorescent bulbs. The New York Times review panel found the Philips Halogena to be pleasing to the eye, and it notes the energy efficiency of this model. A review at Shahine.com by Omar Shahine recommends compact fluorescents for fixtures they fit, but praises the light quality of the Halogena Energy Saver light bulbs. He recommends them especially for use with dimmer switches. User reviews are not particularly plentiful, but a small handful can be found at Amazon.com, where the 70-watt Halogena Energy Saver bulbs earn a rating of 3.5 stars out of 5. Most owners are pleased with the light quality (one says it's slightly more yellow than an incandescent), but there are a few reports of bulbs burning out after about 300 hours of use.
GE also makes energy-saving halogen light bulbs, one of which is recommended in The New York Times review. The GE Edison BT 14.5 (*Est. $30 for five 100-watt bulbs) produced pleasing light, and the review notes that halogen bulbs last twice as long as incandescent bulbs and require less energy in production and distribution. Sylvania has developed the Daylight Plus halogen (*Est. $6 for a 75-watt bulb) and the BT 15 halogen (*Est. $7 for a 60-watt bulb), both of which are intended as incandescent replacements and fit in medium-base sockets.